Underground water, gas, sewer and other utility conduits typically require replacement after an extended period of use, frequently due to corrosion or damage to the conduits. Usually, digging trenches to expose the damaged conduits for replacement is undesirable since this frequently requires destruction of streets, sidewalks, parking lots or lawns, which is unsightly and expensive. To avoid these problems, various techniques and apparatuses have been devised to destroy the conduit in need of replacement and draw a new conduit into place without having to excavate trenches for the operation. Generally, the techniques involve excavating the ground at both ends of the conduit to be replaced and positioning a hydraulic pulling device of selected design in an excavation at one end of the conduit and a cutting tool in the other excavation at the opposite end of the conduit. A rod or cable is extended from the pulling device through the conduit and attached to the cutting tool at the opposite end of the conduit. As the hydraulic pulling device is operated to pull the cutting tool against the conduit, a pneumatic hammer typically intermittently and repeatedly strikes the cutting tool against the conduit, and the combined pulling action of the pulling device and striking action of the hammer on the cutting tool causes the tool to migrate and progressively cut and burst the conduit along the entire length of the conduit. A replacement conduit is typically attached to the cutting tool such that the replacement conduit is drawn into position behind the cutting tool as the cutting tool bursts the old conduit.
An apparatus for bursting and replacing conduits which is characterized by enhanced conduit bursting and replacing capability is needed.